I'm not sure about who actually know about using Twilighte's tools:
- I think Chema used WAVE to compose the music in 1337 (The conversion from 1492 by Vangelis)
- Symoon may know if the CEO mag has articles about how to use Sonix/Wave/Soundtracker/etc...

I don't think Sonic 4 was a proper release. It is a variation on Sonix 3.5 which allowed use of samples. This led to Jonathan writing Soundtracker. Sountracker has a new version of Sonix to play the samples.

Sonic 3.5 version needed Tables.Mem and then Play.Mem loading then the ALL file. The listing then need CALL#5330 : POKE#97F7,0:to play the tune. (I have a listing with these the other way round !?) The Poke turns the channels on. The Call begins play.
I've also got a HIMEM#4E1F at the start with a REM saying always set this limit. I don't remember whether that was to do with the Sonic file or protecting something else.

Rhetoric disk 6 contains SMC - Sonic Music Compiler which turns a Sonix file into a smaller one that is executable. It works with Sonix3.x files but I don't recall ever trying Sonix 4 files. (The disk also contains a full version of Sonix.)

Look to the file 'Example' on the Sonix disk for an explanation of how to use Sonix files in your own tunes.